KIEV (WASHINGTON POST) - Ukraine isn't an American military ally. Its economic connections to the United States scarcely rank. Its troubles with Russia have largely faded from US headlines.

And yet, for the second time since 2016, this country finds itself embroiled in a major Washington scandal.

US President Donald Trump's push to get Ukrainian leaders to investigate the family of Democratic presidential candidate Joe Biden has dragged a war-torn country back into the crosshairs of American partisan politics.

Once again, what happens in Kiev could shape the course of US political fortunes. And once again, Ukrainians are asking themselves why they are getting pulled into the scorched-earth battle zone between Trump and his opponents.

Events in this country, pinched between the European Union and Russia and pulled by eastward and westward forces, have unusual power in Trump-era Washington.

Kiev already played a major role in the scandal that took down Paul Manafort. Trump's 2016 campaign chairman earned millions of dollars advising Ukrainian President Viktor Yanukovych before he was ousted by protests in 2014.

A black ledger detailing Ukrainian government payments to Manafort surfaced in August 2016, leading to Manafort's resignation from the campaign and then contributing to the criminal case that sent him away for seven years for tax and bank fraud.

In the years before Yanukovych's ouster, as Manafort delivered commanding political success to his Ukrainian client, others were studying his work. Although Ukraine is poorer than its Russian neighbour, it has enough cash to fuel a heady life for those who want to join its political trench fighting.

"In Ukraine, many people have quite a lot of money, many people have a bad reputation and want to improve it, and many people want to improve their connection with the West," said Anders Aslund, a senior fellow at the Atlantic Council.

"Ukraine is much more open than Russia, that is the quality, and if you're open, you get more US criminals coming in, also."

Analysts and policymakers say Ukraine - a key transit country for Russian natural gas - draws attention because it has an unusual blend of cash, a history of corruption and competitive elections.

Americans such as Manafort and Trump's personal lawyer, Rudy Giuliani, have found ready clients in Ukraine, where people think US political wisdom can get results.

"In Ukraine, politics is dirty but still competitive," said Andrew Wilson, a senior policy fellow at the European Council on Foreign Relations.

"So you have all sides arming themselves with these techniques."

That's a contrast with Russia, which has far deeper stores of money but where politics has been dominated for two decades by one man: President Vladimir Putin.

The Russian market largely closed to Americans after 2014, when the Obama administration imposed sanctions on Russia for its role in the conflict in Ukraine and business ties dried up.

In Ukraine, Manafort is deeply tied in the public mind to the corruption of the Yanukovych era. When the black ledger of payments surfaced in 2016, diplomats in Kiev figured the disclosure was motivated by Ukrainian anger about his work in their political system. Trump was unpopular in Kiev because of his admiration for Putin, but few thought it was part of a broader Ukrainian vendetta against the Trump campaign, because no one at the time expected the campaign to be victorious.

But in Trump-era Washington, the president's backers have portrayed the episode differently, as part of a Ukrainian government conspiracy to meddle in the 2016 campaign.

Giuliani, whose consulting group counts among its clients several prominent Ukranians, has targeted the former lawmaker Serhiy Leshchenko, who helped publicize the ledger.

In a May appearance on Fox News, Giuliani named Leshchenko as one of a group of "enemies of the president, in some cases enemies of the United States," who were close to newly elected Ukrainian President Volodymyr Zelensky.

Leshchenko says his actions have been distorted.

"Instead of applauding me because I have put in jail a criminal, Mr Manafort, who is found guilty by American judges and American grand juries, they have started attacking me," he said.

Leshchenko advised Zelensky's campaign. But he said Giuliani's vendetta had forced him to leave the new leader's team to avoid harming relations between Ukraine and the United States.

In an opinion article published on Saturday by The Washington Post, he offered to testify before Congress.

But if the end of the Yanukovych era cast out American consultants, including Manafort, the turmoil pulled in others with Washington connections.

One energy company, Burisma, hired several well-connected Democrats, including Hunter Biden, Joe Biden's son, who became a board member in 2014.

At the time, his father was vice-president, and a leader in the Obama administration's response to the crisis in the country.

The younger Biden didn't provide direct support to politicians. He earned up to US$50,000 (S$68,800) per month for his work on the energy company's board, The New York Times has reported, which made some State Department officials uneasy about the potential for an appearance of conflict of interest, former officials said.

Joe Biden has said he never spoke to his son about the Burisma work.

Ukrainian prosecutors launched investigations in 2014 into alleged illegal activities at Burisma, including money-laundering and abuse of office by company owner Mychola Zlochevsky. Zlochevsky and Burisma denied the allegations. One of the probes, for income tax evasion, was settled with a fine. The others never did not result in convictions.

Ukrainian prosecutors have said there is no evidence of improper behavior by Hunter Biden.

Still, Trump and Giuliani have sought to propel Hunter Biden's Ukrainian business dealings into the public sphere.

The Post has reported that an intelligence official filed a whistleblower complaint centering on a July 25 phone conversation between Trump and Zelensky in which Trump asked for an investigation into Hunter Biden.

Trump on Sunday acknowledged raising the Bidens with Zelensky.

"The conversation I had was largely congratulatory, was largely corruption, all of the corruption taking place, was largely the fact that we don't want our people, like Vice President Biden and his son, creating to the corruption already in the Ukraine," Trump told reporters.

Hunter Biden is no longer is on the Burisma payroll. In the Trump era, a different cast of characters is winning contracts in Ukraine.

One of them? Giuliani. His clients include Kharkiv Mayor Gennady Kernes, once an ally of Yanukovych.